The Theory of Everything

December 18, 2013

I noticed this book in the science section of a used book store while searching for an inexpensive copy of an astronomy book I wanted.  Of course the title caught my eye – The Theory of Everything.  Wow, it would be really cool to know the theory of absolutely everything!  Sounded too good to be true! Since I was in a used book store the book was cheap.  It was also short and the author was Stephen Hawking the famous physicist.

One thought struck me as odd. I had never heard of the book before even though I minored in physics in college and follow the topic as I have time. I checked Stephen’s web site. The web site does not mention the book although it does list all his books, lectures, and publications.  Finally, I googled “The Theory of Everything” and discovered  the book is an unauthorized publication of some of his earlier lectures.  Stephen, in fact, filed a complaint with the FTC to stop it’s publication which obviously was not successful. However since I had already purchased the book I decided to go ahead and read it

The first chapter covers the evolution of man’s concept of the Universe starting with the Earth being the center of the Universe. Then the chapter progresses through time ending with Hubble’s discovery that the Cosmos is expanding more and more rapidly.

The second chapter continues with the ever expanding universe evolution.  Many scientists believed the universe to be static and worked diligently to disprove Hubble’s ever expanding universe.  In the end however the ever expanding Universe became universally accepted based partial on the work of:

  • Alexander Friedmann who based upon General Relativity showed the Universe should not be static
  • Penzias and Wilson working at Bell Labs discovered the microwave radiation that started as bright light at the moment of the Big Bang
  • Roger Penrose who proposed the concept of the Black Hole.

Chapter 3 delves into Black Holes in depth. It covers the evolution of the Black Hole concept which was first proposed in 1783 although the term Black Hole was not coined until 1969.  A Black Hole is simply a star sufficiently massive and compact that no light can escape from.  White dwarfs and neutron stars are two closely related concepts.  In all three cases this final state of a star is reached when it has burnt up all it’s fuel (hydrogen). The final state is determined by the mass of the star.  Smaller stars become neutron stars; medium stars become white dwarfs; and larger stars become Black Holes.

Chapter 4 reveals that Black Holes ain’t so Black.  Basically, paired particles (one with positive energy and one with negative energy) near the Black Hole’s Event Horizon break apart. The negative energy particle falls into the black hole while the positive energy particle repels away from the Black Hole’s Event Horizon into the Cosmos. To the outside observer the Black Hole appears to be emitting particles.  An interesting effect on the Black Hole itself is the Black Hole loses energy and mass based on E=MC2.  After a long, long period of time the Black Hole would simply disappear.

Chapter 5 outlines several theories on origin and fate of the Universe. The theories discussed are:

  • The Hot Big Bang Model: Assumes the temperature was infinite at the Big Bang and the Universe will cool off though the eons of time until it reaches absolute zero.  However this model raises some troubling questions such as why was the temperature so hot, why is the Universe so Uniform, etc?
  • The Inflationary Model: This model assumes a very rapid exponential expansion at the beginning. At some point in time the inflationary expansion ended much as water transitions from liquid to solid when it freezes.  This model solves some of the more troubling questions of The Hot Big Bang Model.
  • The No Boundary Condition: In this model there is no beginning or end of the Universe.  There are no Singularities where the laws of physics break down.  The Universe has always existed.  This model is analogous to the surface of the Earth.  If we start at the North Pole the Universe is a single point. As we travel to the Equator the Universe expands then contracts as we close in on the South Pole. Then we start all over again in a never ending cycle. The Universe is neither created or destroyed. The Universe just “is.”

The Direction of Time is the subject of Chapter 6. According to Professor Hawking there are three Arrows of Time:

  • Thermodynamic arrow of time: The direction of time in which disorder or entropy increase
  • Psychological arrow of time: The direction in which we feel time pass
  • Cosmological arrow of time: The direction of time in which the Universe is expanding rather than contracting

The core of this chapter is the direction of the first two times is towards what we perceive as the future.  What a surprise!

The Cosmological arrow of time is also towards the future because the Universe is still expanding.  The question to ponder is will time reverse when the Universe stops expanding and begins to collapse?  The professor believes not. However we have 10s of millions of years before that event so whichever case is true we don’t care.

Finally, the last chapter, we are getting around to the title of the book The Theory of Everything (ToE) refers to a yet to be discovered unified theory that explains the Universe. Currently General Relativity and Quantum Mechanics are two mutually incompatible theories that explain the Universe. That is, they cannot both be correct. Depending on the circumstances either one or the other is used. General Relativity considers only the force of Gravity in explaining for understanding the Universe. Quantum Mechanics uses the three non-gravitational forces (weak, strong, and electromagnetic) in understanding the Universe. Scientist hope to discover the ToE to solve this conundrum. I don’t really understand the weak and strong forces. Perhaps Professor Hawking will write a book “The Theory of the Weak and the Strong?”

At the time of the lectures String Theory and Multi-dimensions  were the most likely candidate.  Close to 20 years have passed since Professor Hawking’s lectures. Still, the ToE has not been discovered and remains the main goal of most physicists.